ADJ [ADJ n]未经思考作出的;依靠本能作出的 If you call someone's response to a question or situation a knee-jerk reaction, you mean that they react in a very predictable way, without thinking. 未经思考作出的;依靠本能作出的 [disapproval]
The knee-jerk reaction to this is to call for proper security in all hospitals.